Nicotine Lozenge Bioequivalence Study: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Nicotine Lozenge Bioequivalence Study (NCT01536704), a randomized phase 1 study. The primary outcome is Area Under the Plasma Concentration Versus Time Curve From Time Zero to Time t [AUC(0-t)].

2. Clinical Question

3. Trial Design

This was a phase 1, randomized, open-label crossover study with enrollment of 50 participants. The registry lists the study as completed, with a start in 2011-07 and primary completion in 2011-08. A crossover design means that comparisons are made within a participant across treatment periods, rather than treating all observations as if each came from a different person. This can help account for stable differences between people, but it also makes the analysis depend on the paired structure and on the handling of period and sequence effects.

The registry describes single doses of two nicotine lozenge doses, 2 mg and 4 mg. The arm descriptions specify test and reference lozenges at each dose, while the posted results label groups as cherry and mint lozenges. The record does not explain this difference in naming. The analysis should therefore be read using the labels attached to the posted outcome groups, without assuming that a particular flavor label corresponds to the test or reference formulation.

The study was unmasked, so treatment identity was not concealed from participants or investigators according to the registry design entry. The primary outcome is a pharmacokinetic measure of plasma nicotine exposure. Blood sampling was scheduled before dosing and at multiple times after dosing, through 12 hours. The primary endpoint description says AUC(0-t) was evaluated using the trapezoid rule and that analysis was done in the intention-to-treat population.

The registry does not report the randomization sequence, treatment-period details, washout duration, sample-size rationale, statistical plan, interim analyses, or the original assumptions used to design the study. Those details matter for interpreting a crossover comparison and cannot be reconstructed from the outcome summaries alone.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Before assignment: Out of 141 participants screened, only 50 were randomized since 91 were screen failures.

Period 1

Washout Period 1

Reasons for not completing this period:

Period 2

Washout Period 2

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Analysis was done per intention to treat (ITT) population.

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Area Under the Plasma Concentration Versus Time Curve From Time Zero to Time t [AUC(0-t)], measured over Blood samples taken pre-dose and post-dose at 3, 5, 10, 15, 20, 30, 40, and 50 minutes, and 1, 1.5, 2, 3, 4, 6, 8, 10 and 12 hours.

The primary endpoint, AUC(0-t), is the area under the plasma nicotine concentration-versus-time curve from time zero to time t. It summarizes nicotine exposure over the period covered by the blood sampling schedule. A larger area indicates greater cumulative measured plasma exposure over that period; it does not by itself describe the full shape of the concentration curve or how quickly the maximum concentration was reached.

The registry reports AUC(0-t) in nanogram (ng).hour (hr)/millilitre (mL), as a mean with standard deviation. Samples were scheduled pre-dose and after dosing at 3, 5, 10, 15, 20, 30, 40, and 50 minutes, and 1, 1.5, 2, 3, 4, 6, 8, 10 and 12 hours. AUC(0-t) was evaluated using the trapezoid rule, which estimates the area by connecting adjacent measured concentrations over time.

Exposure measures are useful in bioequivalence research because they provide a summary of how much drug reaches the circulation over the observed interval. However, similar AUC values do not necessarily mean that every feature of the concentration-time profile is identical. The record also lists time to maximum concentration and other pharmacokinetic outcomes, but the primary endpoint remains the AUC over the stated sampling period. Whether the observed comparison satisfies a formal equivalence criterion depends on the prespecified margin, which is not reported in the registry record.

7. Results Posted in the Registry

• 2mg Mint Lozenge: mean 20.71 versus 18.84 on control; difference 1.87 (95% CI -1.09 to 4.83), standardized effect d = 0.26; z-test p = 0.216.
• 4mg Cherry Lozenge: mean 34.71 versus 18.84 on control; difference 15.87 (95% CI 11.18 to 20.56), standardized effect d = 1.40; z-test p = <0.001.
• 4mg Mint Lozenge: mean 33.68 versus 18.84 on control; difference 14.84 (95% CI 10.82 to 18.86), standardized effect d = 1.49; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

AUC [0-infinity (Inf)]

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • 2mg Mint Lozenge: mean 22.66 versus 21.03 on control; difference 1.63 (95% CI -1.82 to 5.08), standardized effect d = 0.20; z-test p = 0.355.
  • 4mg Cherry Lozenge: mean 37.48 versus 21.03 on control; difference 16.45 (95% CI 10.98 to 21.92), standardized effect d = 1.24; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between 2mg Mint Lozenge and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for 4mg Cherry Lozenge than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The registry lists secondary pharmacokinetic outcomes including AUC from time zero to infinity, time to reach maximum plasma nicotine concentration, apparent elimination half-life, and the elimination rate constant. Numerical group results are available for AUC from time zero to infinity. The record does not report numerical results for the other named secondary outcomes.

For AUC from time zero to infinity, the sponsor-reported same-dose ratios are 0.92 with a 90% confidence interval from 0.88 to 0.95 for the 2 mg comparison, and 1.02 with a 90% confidence interval from 0.98 to 1.06 for the 4 mg comparison. These results have a broad qualitative pattern consistent with the primary endpoint: the 4 mg same-dose ratio is close to 1, while the 2 mg ratio is below 1. The registry does not report the equivalence limits, so the ratios alone cannot confirm a formal equivalence conclusion.

Secondary outcomes can add context because they capture different features of exposure and disposition. AUC from time zero to infinity extends the exposure summary beyond the observed sampling interval by incorporating an estimate of the remaining area. Time to maximum concentration and elimination measures address timing and decline rather than total exposure. Without their numerical results, the full consistency of those measures cannot be evaluated.

Secondary findings generally carry less weight than the primary outcome when they are not the main prespecified question, especially if many endpoints or comparisons are examined. Multiple testing can increase the chance of at least one apparently notable result occurring by chance. The registry record does not report whether multiplicity was addressed. The unadjusted re-calculations for secondary data should therefore be treated as exploratory descriptions, not as independent confirmation of a primary conclusion.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• AUC [0-infinity (Inf)]
• Time to Reach Maximum Plasma Nicotine Concentration (Tmax)
• Apparent Elimination Half-life of Nicotine T(1/2)
• Elimination Rate Constant for Plasma Nicotine: K (el)

9. Statistical Interpretation

10. Statistical Methods Explained

What does AUC measure?

AUC is a continuous outcome: it can take many numerical values rather than falling into categories. In this trial it represents the area under the plasma nicotine concentration-versus-time curve from time zero to time t. The trapezoid rule estimates this area from measurements taken at successive time points. The estimate therefore depends on the schedule and availability of those measurements. The endpoint offers a compact measure of exposure over the sampling period, while other outcomes, such as time to maximum concentration, describe different aspects of the concentration profile.

The registry reports means and standard deviations for the outcome groups. A mean describes the central average on the reported scale. A standard deviation describes how spread out individual measurements are around that mean. It is not an estimate of uncertainty in the mean; uncertainty in a mean comparison is represented by an interval or a test statistic. The reported group summaries do not reveal the distribution of individual values or the within-participant correlation in this crossover study.

Why distinguish arithmetic and geometric means?

An arithmetic mean is the ordinary average of the observed values. A geometric mean is based on multiplicative relationships and is often used for pharmacokinetic measures whose comparisons are naturally expressed as ratios. The sponsor’s results report geometric mean ratios, whereas the simple re-calculations use arithmetic mean differences from posted group summaries. These answer different statistical questions and are not directly interchangeable. A ratio compares relative scale; a difference compares absolute units.

In a crossover trial, a paired analysis can use the fact that the same participant contributes observations under more than one treatment. This can make the comparison more informative by accounting for participant-level differences. A calculation based only on separate group means and standard deviations cannot recover the paired differences or their variability. Thus the unadjusted re-calculations provide a descriptive check, but they do not recreate the sponsor’s crossover analysis.

What do the sponsor analysis and the re-calculation test?

The sponsor-reported method is the Wilcoxon Signed Rank Test, with a geometric mean ratio and 90% confidence interval reported for each same-dose comparison. The Wilcoxon signed-rank approach is a paired method that uses the direction and rank of within-pair differences. The registry labels these analyses as non-inferiority or equivalence. It does not report the margin needed to interpret that classification as a formal pass-or-fail criterion, nor does it report the p-value for these results.

The re-calculations instead report unadjusted mean differences, intervals, and unadjusted p-values. The intervals communicate a range of values compatible with the summary data under the calculation’s assumptions. A p-value measures how incompatible the observed data are with a specified null model; it does not measure the probability that a hypothesis is true, nor does it establish clinical importance. The posted p-values are unadjusted, and no adjustment for multiple comparisons is reported for them.

Why does crossover structure matter?

Randomization helps reduce systematic differences in treatment assignment. In a crossover design, each participant’s experience under one treatment can be compared with that participant’s experience under another. This structure is distinct from an independent-groups design. Ignoring pairing can misrepresent the uncertainty of the comparison because it omits information about how strongly a participant’s measurements under the treatments are related. The record identifies the study as crossover but does not provide the participant-level data needed to reproduce a paired analysis.

Other crossover considerations include treatment period, treatment sequence, and possible carryover from an earlier period. Whether and how those issues were addressed is not reported in the registry record. This is not evidence that they were ignored; it means the posted information does not allow their handling to be assessed.

How should interval estimates be read?

A confidence interval expresses uncertainty around an estimate. In repeated use under the method’s assumptions, intervals constructed in the stated way would cover the target quantity at the stated rate. It is not a probability statement that a particular fixed parameter lies within one already calculated interval. The sponsor intervals are identified as 90% confidence intervals. The confidence level for the re-calculated intervals is not stated in the available record, so they should not be assigned a level by assumption.

For equivalence questions, an interval is judged relative to a prespecified range of acceptable ratios. The point estimate alone is not enough: its uncertainty and its position relative to both limits matter. The registry record does not give the equivalence limits, so the ratios and intervals can be reported, but a formal equivalence determination cannot be independently checked from these entries.

Why can dispersion affect planning?

General statistical explanation: variability affects how precisely a study estimates a treatment contrast. Greater spread in outcomes generally makes it harder to distinguish a given effect from random variation, while lower spread can improve precision. In a crossover study, the variability of within-participant differences is especially relevant. The posted group standard deviations do not supply that paired variability. Therefore, planning illustrations calculated from unpaired summary information should not be treated as a reconstruction of the trial’s original crossover design.

11. Confidence Intervals and Precision

The sponsor’s primary-outcome ratio for the 2 mg groups was 0.91, with a 90% confidence interval from 0.88 to 0.94. For the 4 mg groups, the ratio was 1.02, with a 90% confidence interval from 0.98 to 1.05. These intervals express uncertainty in the relative exposure estimates under the sponsor’s reported method. Their interpretation for equivalence depends on the acceptance range, which is not reported in the registry record.

The unadjusted re-calculation for 2mg Mint Lozenge compared with 2mg Cherry Lozenge estimated a mean difference of 1.87, with an interval from -1.094 to 4.834. The interval includes zero, which is compatible with no arithmetic mean difference under that calculation, while also allowing values on either side of zero. For the comparisons of the 4 mg groups with 2mg Cherry Lozenge, the intervals were 11.18 to 20.56 and 10.82 to 18.86. These intervals are for differences in the posted arithmetic means, not for the sponsor’s geometric mean ratios. Their confidence level is not stated in the registry record.

Precision is not the same as importance. A narrow interval can indicate a relatively precise estimate, but whether the estimate is sufficiently close to 1 for equivalence depends on the prespecified margin. A wider interval leaves greater uncertainty about the size of the effect. The sample sizes contributing to the posted primary outcome summaries range from 45.0 to 47.0 across groups, while the study enrollment was 50. The record does not explain the differences between enrollment and these outcome counts.

The arithmetic-mean intervals also do not incorporate the paired crossover information. They should not be used as if they were the sponsor’s analysis or as the definitive uncertainty estimates for within-participant contrasts. Participant-level paired data and fuller analysis details are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total events. They are illustrations based on the observed effect, not the study’s own original design calculation. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; each scenario targets the stated fraction of the observed effect. The original trial’s sample-size assumptions are not reported in the registry record.

The 80% power column gives the illustrated number of participants per arm for a design that would have an 80% chance of detecting the specified effect if that effect and the planning assumptions were correct. The 90% power column describes the corresponding target with a 90% chance under those same assumptions. These are planning quantities, not guarantees about the result of a future study. They are also not estimates of the probability that the observed trial result is correct.

The rows that plan for 100% of the observed effect use the full effect estimate from the posted comparison. Rows for 75% and 50% of the observed effect consider smaller effects. Smaller effects are harder to distinguish from random variation, so they require more participants for the same target power under the same assumptions. The sample sizes can change substantially across these scenarios, particularly when the observed effect is modest relative to variability.

These calculations use a simplified two-arm framework. The trial itself was a crossover study, and the available illustrations do not incorporate its paired structure or any unreported design features. Accordingly, the figures are useful for understanding how assumptions affect planning, but they should not be read as the actual planned sample size or as observed power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 1.870; pooled standard deviation σ = 7.243.
2. n = 2 × (1.96 + 0.842)² × 7.243² / 1.870² = 235.5, rounded up to 236 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 1.87                      # observed difference in means
sigma <- 7.24322442010463                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(1536704)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 236 (80% power), 316 (90% power)
 75% of observed effect: n per arm = 419 (80% power), 561 (90% power)
 50% of observed effect: n per arm = 943 (80% power), 1,262 (90% power)
power.t.test: 236.5 
Simulated power at n = 236 per arm: 0.797 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

The sponsor’s analysis is the relevant reported analysis for the same-dose formulation comparisons. It uses the Wilcoxon Signed Rank Test and reports geometric mean ratios with 90% confidence intervals: 0.91 (0.88 to 0.94) for the 2 mg comparison and 1.02 (0.98 to 1.05) for the 4 mg comparison. The registry classifies these as non-inferiority or equivalence analyses, but does not report an acceptance margin or a p-value for either analysis.

The unadjusted re-calculations use arithmetic group means and produce mean differences. They do not use within-participant pairing, and therefore do not recreate the sponsor’s crossover method. The differences between the two sets of results reflect different estimands and analysis structures, not necessarily a contradiction. A geometric mean ratio describes relative exposure, while an arithmetic mean difference describes an absolute contrast in the reported measurement units.

For the 4 mg same-dose comparison, the sponsor ratio is close to 1, and its interval includes values below and above 1. For the 2 mg same-dose comparison, the sponsor ratio is below 1 and the interval is below 1. Those descriptions do not establish equivalence or non-inferiority: that conclusion depends on the prespecified margin and the full protocol analysis. The registry does not provide those details. The unadjusted p-values should not be substituted for the sponsor’s analysis, because they address a different calculation and do not test the stated equivalence question.

15. Multiplicity, Missing Data and Analysis Populations

The posted material includes a primary endpoint, several secondary pharmacokinetic outcomes, and multiple treatment-group comparisons. When several outcomes or comparisons are tested, the chance of finding at least one result that appears notable by chance can increase. Statistical approaches can control that risk or designate a hierarchy of outcomes, but the registry record does not report a multiplicity adjustment, testing hierarchy, or other family-wise error strategy.

The sponsor’s same-dose analyses are labeled as non-inferiority or equivalence analyses. A formal assessment normally depends on a prespecified margin and a defined analysis plan. Neither the margin nor enough detail to verify the full decision procedure is reported in the registry record. The sponsor’s ratios and intervals remain the reported results, but the registry entries alone do not allow an independent assessment of whether a formal criterion was met.

The primary endpoint description says that analysis was done in the intention-to-treat population. The record does not explain how that population was defined, how missing concentration measurements were handled, whether participants with incomplete sampling were excluded, or whether any sensitivity analyses were performed. It does not report the missing-data mechanism or describe imputation. Absence of these details does not establish that data were missing or mishandled; it limits the ability to assess how incomplete data could affect the estimates.

The study is identified as a crossover, but the record does not give details of treatment sequence, period effects, carryover assessment, or the exact paired analysis model beyond the reported test name. It also does not report interim analyses or the original statistical analysis plan. Those omissions matter because design and analysis choices can influence both uncertainty and interpretation. The available summaries support a cautious account of the posted comparisons, not a reconstruction of unreported analytic decisions.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: appendicitis (2.1%).

The registry reports serious adverse events by treatment group. There were 0 serious adverse events among 47 participants at risk in 2mg Cherry Lozenge, 0 among 46 in 2mg Mint Lozenge, 0 among 45 in 4mg Cherry Lozenge, and 1 among 47 in 4mg Mint Lozenge. The top serious-event term listed is Appendicitis, at 2.1%. The record does not establish from the summary alone whether that term corresponds to the single serious event in the group listing.

These figures describe events recorded during the study; they do not establish that a lozenge caused an event. The registry lists other adverse events affecting 6, 9, 13, and 15 participants in the same group order, but the summary does not provide enough detail to assess event type, severity, timing, or attribution. Death counts are not reported in the registry record, so they should not be interpreted as zero.

The study enrolled 50 participants and was designed as a short phase 1 crossover study. Safety counts in such a record are descriptive and should be interpreted in light of the study’s size and duration. The registry does not provide a comparative safety analysis or enough information to estimate uncommon risks.

17. What the Result Does, and Does Not, Mean

The posted results describe plasma nicotine exposure after the lozenge groups listed in the registry. The sponsor reported geometric mean ratios for same-dose comparisons, while the available group summaries show arithmetic means and standard deviations. Together, these provide information about average exposure and the uncertainty attached to the reported comparisons, but they do not supply every detail needed for a formal bioequivalence judgment.

A ratio near 1 indicates that the estimated geometric means are close in relative terms. Whether that closeness is adequate for a formal equivalence conclusion depends on the acceptable range defined before the analysis. That margin is not reported in the registry record. The confidence intervals show uncertainty around the ratios, but without the margin they cannot be classified as inside or outside the formal acceptance range.

The unadjusted re-calculated differences between group means should not be read as the sponsor’s crossover analysis. They omit within-participant pairing and compare arithmetic means rather than geometric mean ratios. The comparisons across dose levels also answer a different question from whether formulations at the same dose have similar exposure. Statistical significance in those unadjusted dose comparisons does not establish bioequivalence between formulations.

The primary AUC outcome summarizes exposure during the scheduled sampling period. It does not fully describe the concentration-time profile, and it does not establish effects on smoking behavior, cessation, or other clinical outcomes. Although Smoking Cessation is listed as the condition, the posted outcomes concern pharmacokinetics. No conclusion about clinical benefit or treatment choice follows from these summaries alone.

The study is randomized and crossover, but it is also open-label and relatively small in enrollment. Further protocol and analysis details—including the equivalence margin, missing-data handling, and period or carryover assessment—are not reported in the registry record. The appropriate interpretation is therefore a description of the recorded pharmacokinetic estimates and their uncertainty, with the formal equivalence determination left unresolved by the available registry information.

18. Why This Trial Matters Statistically

This study illustrates why the statistical question must match the trial design and the scientific objective. A bioequivalence question is ordinarily expressed in relative terms, while simple differences between arithmetic means are absolute contrasts. The sponsor’s geometric mean ratios and the unadjusted mean-difference re-calculations therefore should not be treated as competing answers to an identical question.

The crossover structure is central. Since participants contribute measurements under more than one treatment, a paired comparison can use information that is lost when only separate group means and standard deviations are available. Re-calculations from summary statistics can offer a transparent descriptive check, but they cannot reproduce a participant-level analysis or its uncertainty when the paired data are absent.

The record also shows the importance of reporting the acceptance margin for an equivalence analysis. A ratio estimate and confidence interval are informative, but their interpretation as meeting an equivalence standard requires a boundary chosen in advance. Without that boundary, readers can describe how close the estimate is to 1 and how much uncertainty remains, but cannot verify the formal decision.

Finally, a pharmacokinetic endpoint has a defined scope. AUC measures exposure over time, while other measures address timing or elimination. Those results can characterize drug exposure but do not by themselves answer questions about clinical outcomes. Careful separation of design, estimand, uncertainty, and clinical meaning helps prevent a statistically clear contrast from being mistaken for a broader treatment conclusion.

19. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

The registry descriptions use different labels for the study arms. The intervention and arm descriptions refer to test and reference nicotine lozenges, whereas posted outcome groups are identified as cherry and mint lozenges. The record does not explain how those labels correspond, limiting interpretation of which specific formulation is represented by each outcome group.

The study is crossover, but the available summaries do not include participant-level paired data. Consequently, the unadjusted re-calculations cannot account for within-person correlation and should not be treated as a replication of the sponsor’s analysis. Details about treatment sequence, period effects, washout, and carryover are not reported in the registry record.

The formal non-inferiority or equivalence margin is not reported. This is a key limitation because the sponsor’s ratios and 90% confidence intervals cannot independently establish whether a prespecified criterion was met without the margin. The registry also does not report the full statistical analysis plan, the original sample-size justification, missing-data handling, or whether multiplicity was addressed.

Participant characteristics and further eligibility details are not reported in the registry record. The primary outcome counts range from 45.0 to 47.0 by group, compared with enrollment of 50, but the record does not explain the difference. The safety summary provides counts without detailed timing or attribution, and death counts are not reported. Finally, outcomes focus on pharmacokinetics; the posted results do not establish clinical effects on smoking cessation or other health outcomes.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: Nicotine Lozenge Bioequivalence Study — NCT01536704.
• Registry record last updated 2013-04-26; status last verified 2013-03.
• Results first posted 2013-04-26.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

23. Record Summary

NCT01536704 is a completed phase 1 randomized, open-label crossover study with enrollment of 50 participants. It compares nicotine lozenge groups at 2 mg and 4 mg. The primary endpoint is AUC(0-t), calculated using the trapezoid rule from scheduled plasma samples through 12 hours.

The sponsor reported same-dose geometric mean ratios of 0.91 for the 2 mg comparison and 1.02 for the 4 mg comparison, each with a 90% confidence interval. The registry labels these as non-inferiority or equivalence analyses, but does not report the acceptance margin. Unadjusted mean-difference calculations are descriptive and do not reproduce the paired crossover analysis.

The record also includes AUC from time zero to infinity results and adverse-event counts. Numerical results for the other listed secondary outcomes, details of missing-data handling, and several key design and analysis assumptions are not reported in the registry record. The findings describe pharmacokinetic outcomes and do not establish clinical effects on smoking cessation.